Hard vs. Soft chambers

Hyperbaric Oxygen Therapy or “Mild” Hyperbaric Therapy

“Can’t I just buy a chamber and put it into my home?”

The question is not can you, but is it safe and effective. First of all, you cannot legally put a real hyperbaric oxygen therapy chamber into your home. In addition to the National Fire Protection Association (NFPA-99) regulations and the illegality of medical-grade oxygen purchase, it just would not be safe.


What can you legally put into your home? (This is in the US; Canada does not allow even mild hyperbarics in the home.) The question about what is the difference between hard-sided medical grade hyperbaric oxygen chambers and inflatable hyperbaric chambers (mild/soft hyperbarics) is a common asked question. At the Oxford Recovery Center, we use only hard-sided Sechrist chambers. If inflatable bags were an effective treatment modality it would only make sense for us to use them, as the cost would be immensely less expensive for the chamber cost, oxygen (tank, plumbing, corral, and gas), not to mention the extensive NFPA-99 regulations for the build-out. However, hyperbaric oxygen therapy is NOT the same as the mild hyperbarics.


To compare the differences, let’s look at the oxygen in the blood. We measure the changes from arterial blood gases. Arterial oxygen at 2.4 ata 100% oxygen is 1,824 mmHg (normal air pressure is 157mmHg). This refers to how much oxygen is getting into the body, what is making the changes. Compared to using mild/soft chambers, the arterial oxygen at 1.3 ata 24% oxygen is 230 mmHg (normal air pressure is 157mmHg).Now Consider this: If you have a non-rebreather oxygen mask hooked up to an oxygen tank (the oxygen mask you see paramedics use when transporting a patient), the mask can deliver about 55% oxygen. The percentage is used by using the conversion equation (1ATA x 760mmHg x0.55=418mmHg). The moral of the story is that an oxygen mask can deliver a higher amount of oxygen than an inflatable bag so why would you expose yourself to the time and expense for such little benefit.


Let’s examine the reasons why we do NOT use inflatable bags and we do NOT call them hyperbaric oxygen chambers. For a quick comparison:

Hard Chamber

Soft Chamber

100% medical grade oxygen Ambient air (approximately 21% oxygen—mostly nitrogen)
Pressurized typically to a max of 3.0 ATA or depth of 66 feet (Some go to 6.0 ATA or 165 feet) Pressurized to a max of 1.3 ATA or depth of 8 feet
Regrow bone and tissue in severely damaged areas of the body Cannot regrow bone and tissue
Supported by thousands of clinical studies which validate successful healing No such correlation has been made with soft chambers and healing
Many treatments are recognized for reimbursement by insurance companies and federal government No conditions are reimbursed by insurance companies using soft/mild chambers
Designed to go to therapeutic pressures to achieve healing Designed to temporarily treat divers and mountain climbers in route to a hard chamber
Kills harmful bacteria Can promote the undesirable growth of aerobic bacteria
Meets the American Society of Mechanical Engineers, Pressure Vessels for Human Occupancy (“ASME PVHO-1”) standard Does not meet the “ASME PVHO-1” standard
Loss of electrical power has no effect on pressure and oxygen flow Loss of electrical power and chamber rapidly deflates causing possible barotrauma to patient’s ears and pneumothorax to patient’s lungs
No risk of contaminated or polluted air. A closed system of oxygen is piped in directly from a liquid oxygen tank. The liquid oxygen is converted to a gas on-site and pumpled directly into the individual chamber. There is no outside air contamination. Risk of breathing contaminated or polluted air which can be counterproductive
Designed to heal ischemic tissue or tissue that is restricted from receiving enough oxygen by hyper-oxygenating the body, blood and plasma No research shows healing ischemic tissue
Research shows a total of 40 treatments Some results may be obtained in the lower pressure air filled chambers, however it will take many, many more sessions and the results often do not hold, or create issues with yeast or bacteria growth
Designed to use enriched gases like 100% oxygen Never designed to be used with enriched gases like 100% oxygen
Arterial oxygen at 2.4 ata 100% oxygen is 1,824 mmHg (normal air pressure is 157mmHg). This refers to how much oxygen is getting into the body, what is making the changes. Arterial oxygen at 1.3 ata 24% oxygen is 230 mmHg (normal air pressure is 157mmHg).

At Oxford Hyeprbarics our Seichrist Chambers are able to generate 3 ATA of pressure and typical treatment protocols are between 2.0ATA and 2.4ATA. So, at 3.0ATA (3.0ATA x 760mmHg x 100%=2,280mmHg) we can deliver almost ten times the amount of medical grade oxygen to you. At our typical treatment depths we generate 1,520 mmHg of pressure at 2 ATA (almost 7 times as much oxygen) and 1,824mmHg at 2.4ATA (almost 8 times as much oxygen as an inflatable bag.

Oxford Hyperbarics also finds it very important to treat at a research validated protocol. All valid scientific studies demonstrating the benefit of hyperbaric therapy were performed at pressures higher than those able to be achieved in an inflatable bag. You cannot apply those benefits at the much lower pressures from inflatable bags.

The FDA does not recognize inflatable bags as a medical device for hyperbaric oxygen treatment. You will never find them in any reputable hospital or medical office. The FDA only recognizes inflatable bags as a device used to treat altitude sickness during transport to a definitive medical facility. Scientific literature shows that oxygen becomes bacteriostatic (biological or chemical agent that prevents bacteria from reproducing) at 1.5 ATA. Since inflatable bags can only produce 1.3ATA they not only can’t prevent bacteria from growing, they can actually enhance the growth of some molds, fungus, and aerobic bacteria!

Parents and patients are also being informed that they can attach an Oxygen concentrator to the mild HBO to increase Oxygen delivery to the bag’s occupants. This is an immediate concern as the risk of fire is significantly elevated when parents indicate that they are also using computer games and DVDs inside the ‘chamber’ to keep the child entertained. This is completely inappropriate and may well end up with somebody being severely burnt or losing their life! The additional use of Oxygen concentrators and internal use of electronic devices are in direct conflict with manufacturer’s recommendations notwithstanding the USA FDA product standards. Similar standards exist in Australia.

Many of the mild chamber manufacture’s websites makes a deliberate attempt to embrace a range of medical conditions and disorders under the banner of ‘hyperbaric therapy’. The public are ‘none the wiser’. However the evidence supporting the use of Hyperbaric Oxygenation in these conditions and disorders are on the basis of applications using 100% Oxygen at pressures typically 1.75-2.5 ATA or greater. Hyperbaric oxygen therapy is about saturating the body with oxygen. This is most effectively done by delivering 100 percent oxygen through two different pathways: by inhalation through your airways and by absorption through your skin.

It is important to note the difference between Hyperbaric Oxygen Therapy (HBOT) and Hyperbaric Therapy (HBT) also referred to as Mild Hyperbaric. Most mild chambers are inflatable bags originally intended for use in mountain climbing accidents or air sickness and have been substituted for pressurized oxygen therapy. The most significant difference between the two is the “O” as in oxygen. Because Mild chambers do not use 100 percent pure medical grade oxygen it technically cannot be referred to as Hyperbaric Oxygen Therapy and cannot equally be compared to the potency and effectiveness of Hyperbaric Oxygen Therapy.

The bottom line, not all “hyperbarics” are created equal. Do your research, look at the Peer Reviewed research that is out there, think about what makes sense, and think safety first.

When looking for a provider of hyperbaric oxygen therapy inquire about the chambers they use, age of chambers, service records, oxygen provider, do they require a mask or hood, and are their CHT’s on staff and someone who has gone through the Safety Director course.

Want more information? Follow the link to this article by Robert L. Sands: Dispelling the Confusion and Controversy over _Soft_ or _Hard_ Chambers